PDA

View Full Version : Disadvantages of offset rims?



sandwich
08-18-2004, 07:42 AM
What are the disadvantages of switching from positive offset (bolts on outside of wheel) to Zero offset (bolts in center of wheel)?

I'm thinking about buying a car that would look fantastic with a set of fender flares. In order to do that, I'd have to space the wheels out or switch to another set. What would I be doing to my suspension if the offset was boosted out say 1-2"? I've seen cars with widebody kits where the owner has dramatically changed offset, but what does this do to your car?

Matra et Alpine
08-18-2004, 08:02 AM
What are the disadvantages of switching from negative offset (bolts on outside of wheel) to Zero offset (bolts in center of wheel)?
Offset applies to the distance from centre line of wheel looking from the tyre to the face of the wheel that mates to the disc/drum on the car.
See http://www.mgf.ultimatemg.com/wheel_options_for_the_mgf.htm#Offset as pictures are always better than words :)
On newer alloys it's quite common to find a deep central casting which means the bolts seem on the outside but in reality the offest is different.

I'm thinking about buying a car that would look fantastic with a set of fender flares. In order to do that, I'd have to space the wheels out or switch to another set. What would I be doing to my suspension if the offset was boosted out say 1-2"? I've seen cars with widebody kits where the owner has dramatically changed offset, but what does this do to your car?
Thre are SOOOO many 'depends' that I can only give you the 'generic' answers.
First you will be stressing components with forces not expected as the wheels are now effectvely on longer levers. That could lead to breakage and WILL certainly increase wear.
Second, suspension - again with longer levers you first will have the 'wrong' spring and damper settings to the ideal ( however as street cars are so much a compromoise this may not be too significant )
Third, steering. You've moved the contact patch OUT from the position for the optimum caster and ackerman for the steering. It usually means stiffer to turn and more bump steer.
Obviously a few mm will not make a LARGE effect, but a large increase can take a mediocre car and make it the bad :( For a tuned and setup car it is disastrous and needs the geometry reset !!
So if you want to get good handling then you need to pay attention to making a few other adjustments, replacements and strengthening. If you only want to pose and street cruise then it's probably OK as you can cope with 2 and 3 but watch out for point 1 !!!!